1. Field of the Invention
The present invention relates to a display correlator system, but more particularly, it relates to a multipurpose automatic pattern recognition apparatus that makes use of both optical templation and signal correlation techniques.
2. Description of the Prior Art
Automatic pattern recognition is used to interpret signals from sensors to detect and identify unknown patterns. Automatic pattern recognition is used in machine reading typewritten material, product codes (optical character recognition), and signal, object, and target recognition and identification. Automatic pattern recognition is presently accomplished by two methods--optical templating and electronic signal correlation.
The most sophisticated optical templating method is to shine a light image of an unknown pattern through a hologram containing stored known pattern images. If a matching pattern is stored in the hologram, a point of light will be diffracted from the hologram. The position of the point of light can be used to identify which stored pattern in the hologram is a match with the unknown pattern. Deficiencies of this method are that the movement of unknown pattern or orientation or slight differences from the known pattern can substantially affect detection and identification. Large holograms and volume are required for better detection. More than one hologram is needed to make more than a few pattern recognitions.
A sophisticated electronic signal correlation method is to compare and match an electronic signal of an unknown pattern to electronic signals of algorithms of known patterns. Deficiencies of this method are the same as the foregoing method due to slight deficiencies in the algorithm generated pattern. A small amount of noise, obscuration, deletion, or additions can cause these automatic pattern recognition devices not to be able to make any detection or identification.
Large, sophisticated, complex and expensive software and computers are needed for the algorithm generation and comparison. When patterns from different sensors are correlated at one time, very large, complex, and expensive computers and software are required.